net: remove obsolete WARN_ON(refcount_read(&sk->sk_refcnt) == 1)

sk->sk_refcnt has been converted to refcount_t in 2017.

__sock_put(sk) being refcount_dec(&sk->sk_refcnt), it will complain
loudly if the current refcnt is 1 (or less) in a non racy way.

We can remove four WARN_ON() in favor of the generic refcount_dec()
check.

Signed-off-by: Eric Dumazet <[email protected]>
Reviewed-by: Kuniyuki Iwashima <[email protected]>
Reviewed-by: Xuanqiang Luo<[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: edumazet

include/net/sock.h

@@ -830,11 +830,9 @@ static inline bool sk_del_node_init(struct sock *sk)
 {
 	bool rc = __sk_del_node_init(sk);
 
-	if (rc) {
-		/* paranoid for a while -acme */
-		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
+	if (rc)
 		__sock_put(sk);
-	}
+
 	return rc;
 }
 #define sk_del_node_init_rcu(sk)	sk_del_node_init(sk)
@@ -852,11 +850,9 @@ static inline bool sk_nulls_del_node_init_rcu(struct sock *sk)
 {
 	bool rc = __sk_nulls_del_node_init_rcu(sk);
 
-	if (rc) {
-		/* paranoid for a while -acme */
-		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
+	if (rc)
 		__sock_put(sk);
-	}
+
 	return rc;
 }
 

net/netlink/af_netlink.c

@@ -596,10 +596,8 @@ static void netlink_remove(struct sock *sk)
 
 	table = &nl_table[sk->sk_protocol];
 	if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
-				    netlink_rhashtable_params)) {
-		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
+				    netlink_rhashtable_params))
 		__sock_put(sk);
-	}
 
 	netlink_table_grab();
 	if (nlk_sk(sk)->subscriptions) {

net/tipc/socket.c

@@ -3031,10 +3031,8 @@ static void tipc_sk_remove(struct tipc_sock *tsk)
 	struct sock *sk = &tsk->sk;
 	struct tipc_net *tn = net_generic(sock_net(sk), tipc_net_id);
 
-	if (!rhashtable_remove_fast(&tn->sk_rht, &tsk->node, tsk_rht_params)) {
-		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
+	if (!rhashtable_remove_fast(&tn->sk_rht, &tsk->node, tsk_rht_params))
 		__sock_put(sk);
-	}
 }
 
 static const struct rhashtable_params tsk_rht_params = {